Safety device

ABSTRACT

Sensor means for monitoring the awareness status of an individual within a monitored environment ( 50 ) comprising means ( 55 ) for determining the attainment of at least one predetermined condition identifying the requirement for the awareness of an individual to be monitored, and operative to trigger an alarm ( 70 ), means ( 15 ) operable by the monitored individual for inhibiting the operation of the alarm, and delay means for delaying the triggering of the alarm ( 70 ) for a predetermined period after the attainment of the said predetermined condition.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a safety device andparticularly to a safety device for use in situations where it isnecessary to maintain consciousness or at least awareness. Suchsituations include, without limitation, those where an individual atrisk may be otherwise unsupervised.

2. Description of the Related Art

In a hospital or like environment it is important that the consciousnessor awareness status of an individual is known to the staff. This is ofthe utmost importance in connection with patients whose state of healthis uncertain, such as patients undergoing tests, those in hospital forobservation or those convalescing or recovering from an operation.However, there are situations where a patient is not usually supervised,for example, toilet cubicles or washing facilities. If a patient fallsill and becomes unconscious or partly conscious whilst unsupervised inthese situations it may be some time before they are found and locatedso that their condition can be attended to.

Toilet cubicles are particularly relevant in the case of people at riskof cardiac arrest, major pulmonary embolus or hypoglycaemia. It is knownthat many people have a circulatory arrest whilst in a toilet. This isnot coincidental but rather, at least in part, because the vagalreaction makes them think that they need the toilet when it may in factbe an early response to the events leading to the collapse.

There are, of course, other circumstances where consciousness orawareness indications are required. For example it has long been thepractice to provide the driver's cab of a railway locomotive with adevice known as a “dead man's handle” which is to be maintained in anoperative state by the train driver in order to ensure that he has notfallen asleep as a result of the essentially tedious nature of thistask.

Some toilets and bathrooms are provided with emergency cords which mustbe pulled to trigger a signal to attract attention. However, it may notalways be possible for the patient to pull such a cord, for examplebecause they have fallen on the floor and/or are unconscious, or becausethey have become disorientated or confused as a result of a medicalcondition.

There exists the need for a device which requires a patient to dosomething positive to demonstrate that they do not need assistance.

Accordingly, the present invention provides sensor means for monitoringthe awareness status of an individual within a monitored environment,comprising means for determining the attainment of at least onepredetermined condition identifying the requirement for the awareness ofan individual to be monitored, and operative to trigger an alarm, meansoperable by the monitored individual for inhibiting the operation of thealarm, and delay means for delaying the triggering of the alarm for apredetermined period after the attainment of the said predeterminedcondition.

The monitored environment may comprise an enclosed space. In a preferredembodiment the safety device is designed for use in a lavatory cubicle;however, other situations where individuals are not normally supervised,such as bathrooms or shower cubicles, are not beyond the scope of theinvention.

The condition identifying the requirement for the awareness of anindividual to be monitored may be no more than the presence of theindividual in the monitored environment.

The means for detecting the presence of an individual may act eitherindirectly, for example by sensing operation of a door lock, or byremote sensing means sensitive to the presence of an individual within arange thereof, such as an infra red or other light beam or an ultrasonicdetection means. In any case it is preferable that the individual cannotbe present in the monitored environment without being detected. In thecase of a door lock for a toilet it is therefore preferable that theassociated door is biased to be open, by any suitable means, such as aspring. The lock is then required to hold the door closed so that anindividual will be encouraged by this so not use the toilet withoutlocking the door, and in doing so identify the requirement for him orher to be monitored.

In an alternative embodiment the device itself may be attached to orworn by a monitored individual and set to detect when the individualenters an otherwise unsupervised environment, for example a stairwellwhere visual monitoring by staff is not available. When in thisenvironment, the user must maintain a button pressed or provide otherawareness indication to prevent triggering of an alarm.

The positioning of the means for inhibiting the alarm within themonitored environment and its operation is preferably dictated at leastin part by ergonomic considerations, so as to be accessible, comfortableand not inconvenient for the monitored individual to use. The means forinhibiting the alarm may be fixed in its position or movable to alimited extent to allow positioning for convenient use by a userregardless of his or her position in the monitored environment. Likewiseall, or part of the means for inhibiting the alarm may be adjustable forthe comfort and convenience of the monitored individual.

The means for inhibiting the alarm may be formed so as to be operablewhilst a monitored individual is seated or standing and may be operablefor example by a limb, hand, foot or digit, the general principle beingthat the action must be one requiring sentient control.

In a preferred embodiment the means for inhibiting the alarm is a pushbutton pressed by a foot. However other suitable arrangements such as apedal or hand-operated lever or one positioned to be operated by a knee,or a switch to be operated by a digit are not beyond the scope of theinvention.

In a preferred embodiment the means for inhibiting the alarm is a pushbutton which is located on the floor and is upstanding therefrom. It maybe preferable, however, for the means for determining the attainment ofa predetermined condition and/or the means for inhibiting the alarm tocomprise a member which does not protrude substantially above the levelof an associated surface so as not to present a risk of tripping. Forexample the member may comprise a laminar element such as a pressure padto be placed on the floor whereby to be substantially level therewith, amembrane switch or a sunken button. A laminar element may be sensitiveto pressure over part of its surface; markings or other visible indiciasuch as coloured areas may be provided to identify the required positionof the user's feet or other actuating member.

For the visually impaired tactile indicators may be provided, such assurface roughening or small projections.

This principle could also be applied to the means for determining therequirement for monitoring the individual. For example a pressure pad ormembrane switch could be positioned at the entrance of the monitoredenvironment so as to be triggered as the individual enters.

The means for inhibiting the alarm may be resiliently biased to thealarm-activating position so that the bias has to be overcome bymuscular effort to prevent the alarm from sounding.

In order to avoid the possibility that the operating limb, hand or footmay remain on the means for inhibiting the alarm followingunconsciousness or illness, it is desirable for the alarm-inhibitingmeans to require deliberate muscular effort to maintain it in itsoperating position so that muscular relaxation upon loss ofconsciousness will result in the alarm being raised. The effort requiredto operate the means for inhibiting the alarm is therefore preferablymore than that which could be satisfied merely by placing the weight ofthe limb, hand or foot on it.

It is preferable that the bias acts in such a way that it is unlikelythat an individual could or would wish to act against it, eitherdeliberately or inadvertently whilst in need of assistance. The requiredeffort may be variable.

Although operation of the means for inhibiting operation of the alarmmust be deliberate, the operation does not have to be continuous. Forexample, in the case of a lever which is pushed down, the lever maygradually return to its starting position, whereby the individual mustperiodically depress the lever to prevent activation of the alarm.

The means for inhibiting the alarm may further include a guard member orelement which may be positioned to inhibit accidental operation.

In a preferred embodiment the guard comprises a U-shape raised collarand a push button is located in the recess defined therein. However,other means such as a flap or cover which must first be removed couldalso be envisaged.

The alarm may consist of audible, visual or other appropriate signals toalert the attention of supervising staff. The alarm may be localised tothe area of the means for inhibiting the alarm and/or may be connectedto a central monitoring system. Connection of the sensor means to thealarm and/or a central monitoring system may be direct or by telemetry.

The system preferably has means to avoid inappropriate activation of thealarm. For example, in the case of a toilet cubicle, in the normalcourse of events when an individual has finished using the toilet andwishes to leave the cubicle or wants to adjust the position of his orher foot he or she may have to release the means for inhibiting thealarm; it is undesirable for the alarm to sound immediately. This may beovercome by having a predetermined delay between such release andsounding of the alarm; any such time delay should not, however, be solong as to endanger a user with a genuine emergency.

Once the requirement for monitoring the individual is satisfied theremay also be provided warning means which operate during thepredetermined period after the attainment of this predeterminedcondition. The warning means will therefore be effective to serve as areminder to operate the means for inhibiting the alarm, both initiallyas the individual enters the monitored environment and at any timeduring their occupation for example if they remove their foot to adjustits position, until the means for inhibiting the alarm are activated orthe individual leaves the enclosed space. The warning means may comprisemeans for generating an audible; the signal may increase in frequencywith time.

The system is preferably co-ordinated with the presence detector so thatthe alarm function is inactivated once the individual has left thecubicle. There may also be provided further means for deliberatelyinactivating the alarm function, for example a key held by a responsibleperson which may be used if the alarm has activated and staff are inattendance, the alarm no longer being required.

In the case of patients whose mental or physical state makes it unlikelyor impossible for them to operate an alarm-inhibiting device requiringsentient muscular control it may be necessary or desirable to have anindividual such as a healthcare auxiliary in close proximity to themonitored environment. In such cases there may be provided second meansfor inhibiting the operation of the alarm located externally of themonitored environment and operable by a supervisor able to maintainsupervision of the monitored environment. In this case the secondalarm-inhibiting means effectively ensures that the monitoring takesplace.

To prevent the triggering of the alarm, operation of the second meansfor inhibiting the alarm may be required in addition to or instead ofthe means operable by the monitored individual. In the first case,operation of the second means could be used to ensure that thehealthcare auxiliary remains in place in close proximity to themonitored environment. In the second case, operation of the second meanscould be used where the monitored individual, because of disability ormental state, is unable to operate the means for inhibiting the alarm,the healthcare auxiliary inhibits the alarm but is in close proximity tothe monitored environment and may periodically assess their awareness,for example by speaking to the monitored individual to get a verbalresponse.

The second means for inhibiting the alarm may function in the same wayas the means for inhibiting the alarm operated by the monitoredindividual, in that the means are resiliently biased to analarm-activating position (such as a normally-closed switch) and requirea continuous conscious action, such as pressing a button, to avoidtriggering the alarm.

If the alarm sounds for any reason the lock of the cubicle door mayautomatically be opened to allow access to the individual. In hospitalsthis would not usually be needed because cubicles are normally equippedwith means by which they can be opened from outside in an emergency.

The system may be retrofitted to existing enclosed spaces or installedupon initial construction.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the invention will now be more particularlydescribed by way of example, with reference to the accompanyingdrawings, in which:

FIG. 1 is a schematic perspective view of switch means for inhibiting analarm according to a first embodiment of the present invention.

FIG. 2 is a schematic view of the system of the invention in situ in atoilet cubicle;

FIG. 3 is a flow chart illustrating the logical steps in the operationof the sensor means according to the first embodiment of the presentinvention;

FIG. 4 is a schematic perspective view of means for inhibiting an alarmaccording to a second embodiment of the present invention;

FIG. 5 is a schematic perspective view of a system formed as a third,more comprehensive, embodiment of the present invention in situ in atoilet cubicle; and

FIG. 6 is a circuit diagram illustrating the main electrical componentsused in the system forming the third embodiment of the presentinvention; and

FIG. 7 is a schematic perspective view of a system formed as a furtherembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring first to FIG. 1 there is shown switching means generallyindicated 10 for use in a system for inhibiting an alarm. An upwardlyprojecting foot-operated push-button 15 is positioned in the recessdefined by a generally U-shape guard 20. The guard 20 is a raised collarwhich partly surrounds the push-button 15 and serves to preventaccidental depression thereof. The collar stands up from a base 11 whichhouses the switch components and is connected to the circuit by a cable12 allowing the switch to be positioned comfortably for the user.

The push-button 15 is resiliently biased to the raised alarm activatingposition as shown in FIG. 1, and requires a user to apply pressuresthrough his or her foot, such as by a heel 40 to depress it. The switchmay alternatively be depressed by a toe.

Referring now to FIG. 2 the main components of a system for monitoring atoilet cubicle generally indicated 50 are schematically illustrated.These comprise a door 60 with a lock 55 and a toilet pan 30. When anindividual enters the cubicle 50 and operates the lock 55 of the cubicledoor 60, the requirement for the awareness status of the individual tobe monitored is triggered.

The push-button switch 15 is located adjacent the toilet 30 with theguard 20 positioned so as to prevent accidental or inadvertentdepression of the pedal 15 by an individual present in the cubicle 50 inthe vicinity of the toilet 30.

The switch operated by the pedal is closed when the pedal 15 is in theraised position so that, if left in this position, it will cause thealarm 70 to be activated after a delay period as will be described, inorder to allow the individual sufficient time to adjust his or herclothes to make preparation to use the toilet. Once the individual isotherwise ready to use the toilet 30 the push-button 15 is depressed andmaintained in the depressed state by deliberate pressure from the footof the individual to prevent activation of the alarm 70.

Referring now to FIG. 3 there is shown a flow-chart illustrating thelogical steps in the operation of the system of the invention. It willbe appreciated that this is a schematic representation of the underlyinglogical steps and not a representation of the implementation of FIG. 1or 2.

In the normal or monitoring state of the system it checks continuouslywhether an individual is present in the monitored environment. Whilstthe answer to this question is “no” the system operates continuously inorder to maintain a monitoring check on the environment. With theoperation of the door lock 55 the necessary requirement for indicationthat an individual is present is met; after a predetermined delay thesystem checks whether the push-button 15 has been depressed by theindividual. If the answer to this question is “no” the alarm istriggered.

If the push-button has been depressed by the user within the delayperiod the answer is “yes” and after a further short delay (of a fewseconds) the system checks again that the push-button is still pressed.

So long as the answer to this question is “yes” a continuous loopoperates repeating the check every few seconds.

When the pedal 15 is released, either because the individual is in needof assistance or is simply in the process of leaving the cubicle 50, theresponse to the monitoring check will indicate that the push-button isnot still depressed. Then, after a predetermined delay the system checksif the individual is still present (indicated by the same means 55 asinitially detected this status as discussed above). If the answer tothis question is “no”, the individual has left the cubicle 50 and thesystem returns to the initial state to maintain a monitoring check forthe arrival of a new occupant. If the answer to this question is “yes”this indicates that the individual may be in need of assistance and thealarm 70 is immediately activated.

Referring now to FIG. 4 there is shown alternative switch means suitablefor use in inhibiting an alarm, generally indicated 110. This switch issuitable for permanent fixing to the floor of a monitored environment. Agenerally L-shape guard 120 comprises lower column or support 130 fromwhich a transverse arm 135 projects laterally. The support 130 extendssubstantially vertically from the ground. At the upper end of thesupport 130 the transverse arm 135 extends generally orthogonally toform the L-shape guard 120. Within the included angle defined by theguard 120 a trigger lever 115 depends from the transverse arm 135. Inuse the foot 140 of an individual is introduced under the transverse arm135 to reach the trigger lever 115 which is then pushed laterally in thedirection shown by the arrow A towards the support 130 to the positionshown in phantom outline to inhibit the alarm. The force required tomaintain the button depressed will require that if the user losesconsciousness and experiences muscle relaxation the trigger lever 115will more back to its original position and trigger the alarm asdiscussed above.

Referring now to FIG. 5 the main components of a second embodimentmonitoring system for a toilet cubicle generally indicated 250 areschematically illustrated. These comprise a door 260 with a lock 255 anda toilet pan 230. The door 260 is resiliently biased to an open positionby the operation of a spring 265 illustrated only schematically, andwill therefore not remain closed unless the door is held shut, forexample by operating the lock 255. When an individual enters the cubicle250 and operates the lock 255 of the cubicle door 260, the requirementfor the awareness status of the individual to be monitored is triggered.

In this embodiment the switch means for inhibiting the alarm are formedas a portable unit generally indicated 210 similar to that in FIG. 1. Agenerally semi-circular guard 220 has a raised collar defining a U-shaperecess. In this embodiment the guard 220 is made of rubber so as to bedurable and hard-wearing. A push button 215 is positioned in the U-shaperecess of the guard 220 for opening a switch within the body of thedevice.

The switch means 215 are kept closely adjacent the toilet pan 230 andare in contact with the necessary components of the sensor device via awire 240. In other embodiments (not shown) a remote (i.e. wireless) linkmay be used.

The push button 215 is shown in the raised, alarm-activating positionand if left in this position will cause an alarm 270 to be activatedafter a delay period as will be described, in order to allow theindividual sufficient time to adjust his or her clothes to makepreparation to use or leave the toilet 230 or adjust his or her footduring use. Once the individual is otherwise ready to use the toilet 230the push-button 215 is depressed and maintained in the depressed stateby deliberate pressure from the foot of the individual (not shown) toprevent activation of the alarm 270 as before. The system also includessecond means for inhibiting the alarm indicated 290 located outside thetoilet cubicle 250. The second means 290 is preferably a hand-heldswitch having a push-button 295 which is resiliently biased to the alarmactivating position.

The delay period defines a period of time during which the requirementfor monitoring the individual is satisfied and the push button 215 isnot depressed but the alarm 270 is not activated. During this time analert 280 sounds to serve as a reminder to the individual that thepush-button 215 needs to be depressed or else the alarm 270 will beactivated.

The alert 280 produces an audible signal which increases in frequencywith time.

The second means 290 is located outside the toilet cubicle 250 so as tobe operable by an attendant. The push-button 295 must be depressed atall times the occupant remains within the cubicle if he or she is unableto press the button 215 this prevents the attendant from leaving theimmediate area. The attendant must thus remain in close proximity to themonitored individual and may periodically determine the awareness of themonitored individual, for example by verbal contact.

Referring now to FIG. 6 there is shown a circuit diagram illustratingthe components required for the operation of the third embodiment of theinvention.

The circuit comprises a door lock switch 345 operated by the door lock255, an alarm-inhibiting switch 346 operable by the push button 215, anexternal alarm inhibiting switch 390 operated by the hand held unit 290,a delay circuit 348, an alarm 370, an alerting circuit 380, a relay 347,an alarm cancel switch 349, a master alarm cancel switch 350 and awarning light 360.

The door lock switch 345 is a normally open switch and is closed by theoperation of the door lock 255 (of FIG. 5).

The external alarm inhibiting switch 390 is a normally closed switch andcan be opened by operation of the push-button of the hand unit 290(shown in FIG. 5) by an attendant.

The alarm inhibiting switch 346 is a normally closed switch and can beopened by operation of the push-button 215 (shown in FIG. 5) by themonitored individual.

The switches 345, 390, 346 are all connected in series, such that whenthe door is locked and neither of the push-buttons 290, 215 are opened acurrent will flow to the delay circuit 348.

The delay circuit comprises a resistor 348 a, a diode 348 b in parallelwith it and a capacitor 348 c which is connected between the resistor348 a and a ground line 381.

If all three switches 345, 346, 390 are closed current flows through theresistor 348 a and charges the capacitor 348 c to produce a steadilyincreasing voltage at the alerting circuit 380 and the relay 347. Thealerting circuit thus produces an audible signal the frequency of which,being voltage dependent, gradually increases.

The relay 347 comprises a coil 347 a and relay contacts 347 b. When thevoltage from the delay circuit 348 reaches a threshold level the currentthrough the coil is sufficient to close the relay contacts 347 b and thealarm 370 is activated.

The relay 347 is self-latching in that, when the switch 347 b is closedcurrent also flows via a diode 349 a, through a normally closed alarmcancel switch 349 to the coil 347 a. With this loop active, the switch347 b will remain closed even if any of the switches 345, 390, 346 arethen opened to stop the current flowing through the delay circuit,because the alarm cancel switch directs current through the coil 347 airrespective of the status of these switches 345, 390, 346. If all ofthe switches 345, 390, 346 are closed, operating the alarm cancel switch349 will not stop the alarm 370. However, if one or more of the switches345, 390, 346 are opened again, indicating that there is not in fact anemergency, the alarm cancel switch 349 can then be operated to stop thealarm 370.

When an alarm condition exists and the alarm 370 is active, akey-operated master alarm cancel switch 350 is operable to stop thealarm 370 to allow remedial or resuscitation work to be carried outwithout the added stress of the alarm sounding throughout thisprocedure. However the switch 350 is a changeover switch so that whenthe alarm 370 is stopped in this way a warning light 360 is illuminatedto indicate this fact, and to alert staff to the need to reset theequipment when the current emergency is over.

FIG. 7 shows further embodiment having alternative means for identifyingthe requirement for monitoring an individual, and alternative means forinhibiting the operation of the alarm. A toilet cubicle is generallyindicated 450 and comprises a door 460 with a lock 455 and a toilet 430.A pressure sensitive pad 495 is located on the floor immediatelyadjacent the door 460. The pad 495 is a laminar element which does not,therefore, present a risk of tripping. The dimensions and positioning ofthe pad is such that when an individual enters the cubicle 450 therequirement for the awareness status of the individual to be monitoredis triggered. A second pressure sensitive pad 496 is located on thefloor adjacent the toilet 430 again the pad is a laminar element anddoes not present a risk of tripping.

Markings 497 define an area on which the user's feet are to be placed;the pad can be moved to allow it to be positioned comfortably for theuser. Within the pad 496 defined by the markings 497 are switches 498(shown schematically). The switches 498 are operated by pressure and areidentical in function to the pedal 15 already described in relation toFIG. 1.

The mere presence of the markings 497 and the requirement to place thefeet in predetermined positions represents a first level of monitoringof awareness as this act requires a conscious effort. A second level isachieved by the requirement for pressure to be exerted and maintainedupon the switches 498.

In addition, in this embodiment the area of the pad 496 not occupied bythe markings 497 is an ‘exclusion zone’, as defined below.

An important feature of this embodiment is that, in addition to pressurebeing required on the markings 497 to inhibit the alarm, it is also arequirement that there is no pressure on the remainder of the pad496—the exclusion zone 499. This is to remove the possibility that anindividual falls and yet remains in contact with one or both of themarkings 497. Therefore, contact on the markings 497 inhibits the alarm470, whilst contact on markings and the exclusion zone does not. Theexclusion zone 499 overrides the inhibitory effect of the markings 497.

1. Sensor means for monitoring the awareness status of an individual within a monitored environment comprising means for determining the attainment of at least one predetermined condition identifying the requirement for the awareness of an individual to be monitored, and operative to trigger an alarm, means operable by the monitored individual for inhibiting the operation of the alarm, and delay means for delaying the triggering of the alarm for a predetermined period after the attainment of the said predetermined condition, wherein the means for inhibiting the alarm are resiliently biased to an alarm activating position such that the means for inhibiting the alarm requires deliberate muscular effort to overcome the resilient biasing, further comprising second means for inhibiting the operation of the alarm located externally of the monitored environment and operable by a supervisor able to maintain supervision of the monitored environment.
 2. Sensor means as claimed in claim 1, in which the monitored environment comprises an enclosed space.
 3. Sensor means as claimed in claim 1, in which the monitored environment is a cubicle.
 4. Sensor means as claimed in claim 1, in which the monitored environment is a lavatory cubicle.
 5. Sensor means as claimed in claim 1, in which the means for determining the attainment of a predetermined condition detects the presence of a monitored individual within the monitored environment.
 6. Sensor means as claimed in claim 5, in which said means for detecting the presence of a monitored individual act indirectly by sensing operation of a door lock.
 7. Sensor means as claimed in claim 5 in which the means for detecting the presence of the monitored individual act by remote sensing means sensitive to the presence of an individual within a range thereof.
 8. Sensor means as claimed in claim 1 in which the means for inhibiting the alarm are operable by a limb of the monitored individual.
 9. Sensor means as claimed in claim 1, in which the means for inhibiting the alarm are operable by a foot of the monitored individual.
 10. Sensor means as claimed in claim 1, in which the means of inhibiting the alarm comprise a pedal.
 11. Sensor means as claimed in claim 1, in which the means for determining the attainment of a predetermined condition and/or the means for inhibiting the alarm comprise a member which does not protrude substantially above the level of an associated surface so as not to present a risk of tripping.
 12. Sensor means as claimed in claim 1, further comprising warning means which operate during the said predetermined period after the attainment of the said predetermined condition.
 13. Sensor means as claimed in claim 12, in which the warning means comprise means for generating an audible signal.
 14. Sensor means as claimed in claim 1, in which the means for inhibiting the alarm further comprise a guard for preventing accidental operation. 